Tamara Micner’s play “Fantasmagoriana,” which has been brought to C Aquila by Cambridge’s ADC theatre, initially appears to be an odd theatrical quirk with very little point to it. We find ourselves in Lord Byron’s Villa Diodati, which is separated from Lake Geneva by an interminable downpour of virtually English rain. The foppish doctor John Polidori had got Byron all to himself in the Villa, but Shelley and Mary Godwin have turned up, followed by the frustrated Claire Clairmont. It strikes Byron that Mary has the makings of a future writer, and that she could follow in the footsteps of her infamous mother. Byron proposes a writing contest, only to encourage Mary, and he selects her favourite genre of Gothic horror.

This intellectual elite – with the unhappy Clairmont in tow – bicker and idly plot, Byron gives up altogether on his piece, but Mary finds a germ of inspiration for a promising horror story. And the rest, as they say, is history.

It is now a customary exercise on stage and screen to follow the circumstances behind the creation of a literary masterpiece, and a range of figures from Keats to Capote have been treated to such “biopics.” “Fantasmagoriana” was on thin ice with myself because I do not rate any of the Romantics very highly – to my ears, Polidori sounds a better writer than Byron – and these people were going to get nowhere trying to compose horror stories at a time when Sheridan Le Fanu had been scarcely born (whatever Frankenstein represents, it is not frightening). Moreover, the scrappy events at the Villa turn out to be only a distraction from Mary’s writing, rather than exerting any discernable influence over it.

So why is “Fantasmagoriana” such a pleasure to watch? It is immaculate from top to toe, spruce and twinkling with mischief. A lot of its success can be attributed to the cast – Adam Drew is a boorish but moodily sober Byron, who dominates the stage; Katie Alcock is delicious as Mary, whilst Jack Oxley is a sensation as both the tormented doctor and the roaming monster. Yet the comedy is decanted carefully and in modest quantities, and the play never loses its head, remaining anchored in the listless but tender exchanges between the peeved Shelley and his understanding mistress, rather than running off with the superb Polidori.

What does it mean? Why has it been written? Perhaps there is only truth to the story, and Frankenstein had indeed emerged from a tawdy and unremarkable set of circumstances. Yet whilst this play struggles to articulate any further rationale, it remains utter delightful and one wishes that it could go on all night.